Recently, much progress has been made in increasing the brightness of light emitting diodes (LEDs), also in relation to “small” LEDs having a compact form factor. As a result, LEDs have become sufficiently bright and inexpensive to serve as a light source in for example lighting systems with adjustable color. By mixing differently colored LEDs any number of colors can be generated, e.g. white. An adjustable color lighting system is typically constructed by using a number of primary colors, and in one example, the three primaries red, green and blue are used. The color of the generated light is determined by the LEDs that are used, as well as by the mixing ratios. To generate “white”, all three LEDs have to be turned on. By using LEDs it is also possible to decrease the energy consumption, a requirement which is well in line with the current environmental trend.
As a further consequence of having the possibilities to provide bright light even when using compact LEDs, a number of different lighting systems have been proposed greatly differing from the standard lighting systems comprising a common light bulb. In line with this and by using LEDs instead of light bulbs, a user is also given a more flexible control of the illumination functionalities of the lighting systems, for example in relation to intensity dimming.
An example of such a lighting system is disclosed in U.S. Pat. No. 7,258,469, where an integral contact-sensitive layer located over the light-emitting surface of a flat-panel touch lamp controls the activation and deactivation of the lamp. The light-emitting surface of this flat-panel touch lamp may be activated (to emit light) or deactivated by means of a user's touch of the light-emitting surface.
However, even though the touch lamp of U.S. Pat. No. 7,258,469 provides improved functional control, it is limited to static activation/deactivation of the light-emitting surface of the lamp, and it may thus be desirable to provide even more intuitively adapted user control of a lighting system, such as a luminaire, for example regarding more degrees of control of the luminaire illumination functionalities.